We plan to continue to offer services to both the North American and European scientific communities for MHC typing of macaques. This will include PCR-SSP tests for alleles encoding MHC class I and II molecules that bind peptides derived from SIV. Additionally, we will continue to offer training for individuals who wish to set up MHC typing in their own laboratories. Finally, we will continue to develop a panel of well-characterized cell lines that will be invaluable for the analysis of the MHC in the macaque. To date, we have typed more than 15,000 macaques for approximately 50 investigators using over 114,000 tests. These typings have supported the publication of over 75 manuscripts. The two specific aims of this application are, therefore, to: I. Offer MHC typing of the class I and II loci for investigators working with Indian rhesus macaques. II. Expand our menu for the molecular typing of the macaque's class I and II alleles. PUBLIC HEALTH RELEVANCE (provided by applicant): SIV infection in macaques is the best animal model to study HIV-infected humans. Furthermore, SIV challenge of vaccinated macaques is critical to HIV vaccine development. Understanding the MHC molecules of the macaque is central to both pathogenesis and vaccine studies.